100% Polyester - Built from a resilient mesh, the Blitzing Stretch Fit Cap hugs your head while still letting it breathe. This means that this hat won’t flop around while running, tip forward while bending, or stay wet while sweating. And that’s because our unique Moisture Transport System brings moisture to the surface so you stay cooler, drier, and more comfortable than ever. Combine that with a classic baseball design, and you’ve got yourself your new favorite hat.